docs(changelog): credit the not-synced state to its own issue (#78)

Splitting it out: dropping a control is a product decision with its own
thread, separate from #76's read-only marker and picker footer.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -10,10 +10,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Settings → Calendars now says what is different about a calendar instead of
   leaving you to guess. Ones you can only view — a subscribed calendar, a
-  calendar shared with you read-only — are marked **Read-only**. Ones whose
+  calendar shared with you read-only — are marked **Read-only** ([#76]).
-  account isn't syncing events to this device are marked **Not synced**, moved
+- Calendars your device isn't syncing are marked **Not synced**, moved to the
-  to the bottom of their account and left without a switch: none of their events
+  bottom of their account and left without a switch. None of their events are on
-  are on the device, so switching one on could not show you anything ([#76]).
+  the device, so the switch they used to have could not have shown you anything
+  — the calendar simply looked broken. Whether an account syncs a calendar stays
+  that account's own app's decision ([#78]).
 - The calendar picker in the event form and in the .ics import screen now ends
   with a **"Missing a calendar?"** row that opens Settings → Calendars, where
   those marks then explain why a calendar isn't offered ([#76]).
@@ -1147,3 +1149,4 @@ automatically, with zero telemetry and no internet permission.
 [#70]: https://codeberg.org/jlmakiola/calendula/issues/70
 [#75]: https://codeberg.org/jlmakiola/calendula/issues/75
 [#76]: https://codeberg.org/jlmakiola/calendula/issues/76
+[#78]: https://codeberg.org/jlmakiola/calendula/issues/78